Drafting head



U ted States Pat nt A I DRAFTING HEAD Olle E. Sandelin, Cleveland, Ohio, assignmto The Warner & Swas'ey Company, Cleveland, Ohio, a corporation of Ohio Application May 16, 1952, Serial No. 288,180

4 Claims. (Cl. 19- -131) This invention relates to the drafting of fiber strands, such as sliver and the like, and to a method of and ap paratus for facilitating such operations particularly upon crimped fibers. 7

An object of the invention is to draft crimped fibers without bunching or similar cumulative effects.

An object of the invention is to draft crimped fibers in discreet stages and to maintain uniforniity of fiber movement in each stage. t

Another object ofthe invention is to control fiber movement in drafting strands including at least some crimped or synthetic fibers.

Still another object of the invention is to control fiber movement in drafting strands of crimped fibers and to eliminate the bunching and avalanching which has heretofore been a concomitant of such operations.

The apparatus and method of the present invention is intended to be used in the drafting of crimped textile fiber or other such fibers having low interfiber resistance to relative movement and, in particular, constitutes a second drafting stage for use after the first stage described in application, Serial No. 285,185, filed April 30, 1952. The invention together with the objects and features thereof will be more readily understood from a consideration of the following detailed specification and claims taken connection with the appended drawings, in which:

Fig. 1 is a vertical section view of a drafting head incorporating the present invention;

Fig. 2 is a view in perspective of the, suction box of the invention;

.Figs. 3, 4 and 5 are views of the condenser of the apparatus of the invention;

Fig. 6 is a vertical sectional view taken along the lines 66 of Fig. 1 showing a first step in the reduction of the sliver strand;

Fig. 7 is a vertical sectional view taken along the line 7-7 of Fig. I and showing a second step in the reduction of the sliver strand;

Fig. 8 is a vertical sectional view taken along the lines 8-8 of Fig. 1 showing particularly the manner of cooperation of the pressure roll and the upper and lower aprons;

Fig. 9 is a top view of a portion of the guide bar and guide bar support showing the guide bar spring;

Fig. 10 is a side view of the guide bar support showing the arrangement whereby the guide bar spring tension may be adjusted; and

Figll is a fragmentary view of the lower apron of the invention.

Referring now to Fig. l, the drafting head 10 therein illustrated includes a pair of feed rolls 11 and 12 at the feed end of the head and a pair of draft rolls 13 and Her the lead end of the head. The pairs of rolls 11 and'lZ, and 13 and14 may be appropriately adjusted to provide a suitable nip as is well known in the art. The feed rolls 11 and 12 may be the draft rolls of a preceding 2,813,307 Patented Nov. 19, 1957 2 drafting head and the sliver strand 15 consequently in such form or condition as results from the operation of the preceding head. In particular, the preceding head may be of a form disclosed in the application. just referred to, and the sliver 15 in four separate strands.

Disposed within the head between the pairs of feed rolls and draft rolls is included apparatus for maintaining the resistance between crimped fibers, or the like, comprising the strands moving between the feed rolls and the draft rolls. The strands are carried upon a lower apron 16 which comprises a strip of flexible material of suitable width and is supported along the path of the sliver by the upper surface 17 of the top wall 18 of a suction box 19. The upper surface 17 of the suction box 19 is formed so as to provide a smooth support surface for the apron 16 and includes an approach portion 20 which provides a smooth transition for the apron from an idler roll 21 to the top surface 17 of the suction box. An .arcuate portion 22 at the lead end of the suction box 19 provides a smooth return transition for the apron. A drive roll 23 is provided for driving the apron while idlers 24 and 25 are provided for maintaining a proper tension in the apron. The apron 16 includes a succession of openings 26 centrally along the length of the apron as is shown in Fig. 11 and described further in the application referred to above.

The suction box 19 is formed as an air-tight enclosure having an exhaust portion 27 adapted to be connected to a pump or the like for exhausting air from the box. The top wall 18 of the box is provided with a succession of openings 28 of generally elliptical form and having the major axis thereof disposed obliquely with respect to the longitudinal axis or direction of motion of the apron 16. This arrangement of the openings 28 aids in the reduction of flutter as is described in application, Serial No. 252,692, filed October 23, 1951 by O. E. Sandelin, now Patent No. 2,659,936. In accordance with the present invention, there is provided, in addition to the obliquely disposed openings 18, an elongated opening 29 at the feed end of the suction box and a similar elongated opening 30 at the lead end of the suction box for reasons to be subsequently described.

There is provided at the feed end of the head a condenser 31 for combining the plurality of strands proceeding from between the feed rolls 11 and 12 into a single strand. The condenser 31 is formed in two portions, an inlet portion 32 including a funnel-shaped opening 33 for affecting a reduction of the strands in a horizontal direction. The opening 33 converges toward an opening 34 in the body portion 35 of the condenser which latter opening is tapered downwardly toward the apron 16. This convergence of the opening 34 toward the apron alfects a reduction of the strands in a vertical direction.

In order to increase the efiectiveness of the suction produced by the suction box in controlling the resistance between the fibers of the strand while the strand is moving along the lower apron, further apparatus is provided in accordance with the invention for producing downwardly directed compressive forces on the strand. Included is an upper apron 36 comprising a strip of thin flexible material of the same width as the lower apron 16 and maintained in running engagement With the lower apron. The material of the strip is of course sufficiently flexible to permit the strip to conform to the body of the strand as is described in the application previously referred to. The upper apron 36 is reevcd around a pressure roll 37, an idler 38, and a guide bar 39 all mounted upon and supported by side plates 40 and 41 of the suction box 19. The idler 38 and guide bar 39 are mounted in bearing openings formed in the side plates 40 and 41, while the pressure roll 37 is supported by bracket members such as the member 42 mounted in elongated openings 43 and 44 in the side plates 40 and 41. The support brackets 42 are formed with vertically elongated openings for receiving the reduced diameter shaft portions 49 of the pressure roll 37, as is shown in Fig; l, to permit free movement of the pressure roll in a vertical direction. The roll may thus rest freely upon the apron 36 exerting a pressure equal to the weight of the roll upon the apron. The pressure roll 37 may, of course, be suitably weighted as is well known in the art in order to provide the proper pressure upon the apron. The longitudinal adjustability of the brackets 42 in the openings 43 and 44 enables an optimum adjustment of the pressure roll 37 for varying conditions of fiber length, type of material and the like.

A guide bar 39 is fixed to a pivotally mounted shaft shown at 45 in Figs. 1 and 9. A torsion spring 46 is connected to the shaft 45 at one end thereof and may be received in any of a plurality of openings 47 in the side plate 41 for adjusting the tension of the spring and, consequently, the pressure exerted by the nose 48 of the guide bar upon the upper apron. The apron 36 moves about the nose 48 of the guide bar 39 which provides a soft or faint nip upon the strand as the strand leaves the aprons.

In operation, a plurality of strands of fiber as, for example, four strands leave the fed rolls 11 and 12 and pass into the condenser 31. The several strands are gathered together in a horizontal direction by the funnelshaped walls of the opening 33 of the inlet portion 32 of the condenser 31. The composite strand thus formed has a relatively great vertical extent at the entrance to the opening 34, as shown particularly by the vertical sectional view of Fig. 6, in which the strand 50 extends between the lower apron 16, the opening 34 and the bottom surface 51 of the condenser plate. As the strand is moved along the length of the condenser plate, the strand is reduced to a relatively small vertical extent as shown at 52 in Fig. 7.

The suction box 19 cooperates with the condenser 31 in that the elongated opening 29 extends to a position under the opening 34. Due to the exhausting action of the suction box, a flow of air is produced into the spaces 53 and 54 between the condenser plate and the apron 16 and through the openings 26 in the apron. The pressure of air upon the sides of the strand thus results in a positive control of the horizontal movement of the strand 50 during the reduction process.

As the strand leaves the condenser 31, it passes between the upper apron 36 and the lower apron 16. The disposition of the aprons is such that the withdrawal of air through the openings in the lower apron together with the pressure of the pressure roll upon the upper apron serves to maintain a positive control of interfiber friction along the length of the strand as it moves between the aprons toward the lead end of the head. It will be seen that the constraining action of the pressure roll 37 on the upper apron will cause the strand to be held by and move with the aprons.

The pressure imposed upon the strand by the guide bar 39 allows fast moving crimped fibers to be stretched by the action of the draft rolls while passing through the end region of the aprons, while slow running fibers are held between the moving aprons, thus providing additional fiber control in the drafting process.

The row of elliptical obliquely disposed holes in the top wall of the suction box is provided to keep the aprons parallel to the wall of the suction box while they are moving under the pressure roll in any one of the positions of the pressure roll. The pressure roll is adjusted to a position in which it is at an equal or slightly greater distance from the draft rolls than the length of fibers to be drafted.

It is to be understood that the specific nature of the present disclosure is not intended to be restrictive or confining and that various rearrangements of parts and modi- 4 r fications of design may be resorted to without departing from the scope or spiritof the invention as herein claimed.

What is claimed is:

1. In a drafting head, a pair of feed rolls and a pair of draft rolls defining a drafting zone having a feed end and a lead end, a pair; of aprons disposed between the rolls, the said two aprons being in running engagement for conducting fiber strands from the feed rolls to the draft rolls, means for exhausting air from between the aprons including an air pervious portion extending along the entire circumference of a first one of the said aprons and suction producing means engaged with, the inside of the first apron for drawing air through the openings in said first apron, a pressure roll engaging the second apron for urging the second apron toward the first apron, and a condenser mounted between the feed rolls and the said aprons at the feed end of the aprons, said condenser comprising a member having a first portion including a horizontally convergent opening and a second portion including an opening tapered toward the said first apron for reducing a plurality of strands into a single strand and aligning the strand with the pervious portion of the first apron.

2. The combination of a strand supporting means comprising a strip of flexible material adapted to be disposed between the feed and draft rolls of a drafting head for carrying strands of fiber between the rolls, the strip having openings for passage of air, means for drawing for drawing air through the openings of the strip and into the box, the box being adapted to be connected to an exhaust pump or the like, means cooperating with the strip for reducing a plurality of strands into a single strand comprising a condenser mounted at the feed end of the strip, said condenser comprising a member having a horizontally convergent opening and an opening tapered toward the strip extending from the horizontally convergent opening, and means disposed above said strip for exerting pressure on the strand along the length of the strip comprising a second strip of flexible material and a pressure roll mounted so as to rest upon said second strip, at least some of the openings in the said suction box being generally elliptical in cross section and having the major axis thereof obliquely disposed with respect to the path of travel of the said strips and adjacent the pressure roll, and mountings for the said pressure roll having vertically elongated openings for receiving the bearing ends of the pressure roll to permit a vertical movement of the roll and to maintain engagement of the roll with the said second strip.

3. In a drafting head, a pair of feed rolls and a pair of draft rolls defining a drafting zone having a feed end and a lead end, a pair of aprons disposed between the rolls, the said two aprons being in running engagement for conducting fiber strands from the feed rolls to the draft rolls, a succession of openings along the length of a first one of said aprons, suction producing means engaged with the said first apron for drawing air from between the aprons, and a pressure roll engaging the second apron for urging the second apron toward the first apron, and a condenser mounted between the feed rolls and the said aprons at the feed end of the aprons, said condenser comprising a member having a first portion including a horizontally convergent opening and a second portion including an opening tapered toward the said first apron for reducing a plurality of strands into a single strand, the said suction means comprising a closed member having an elongated opening disposed adjacent the tapered opening of the condenser member for drawing a strand in the second named opening toward the said first apron,

4. In a drafting head, a pair of feed rolls and a pair of draft rolls defining a drafting zone having a feed end and a lead end, a pair of aprons disposed between the rolls, the said two aprons being in running engagement along the zone for conducting fiber strands from the feed rolls to the draft rolls, a first one of the said aprons having an air pervious portion extending along the length thereof, suction producing means engaged with the under side of the said first apron for drawing air from between the aprons, a pressure roll and a guide bar engaging the second apron for urging the said second apron toward the said first apron, and a condenser mounted between the feed rolls and the said aprons at the feed end of the aprons, said condenser comprising a member having a first portion including a horizontally convergent opening and a second portion including an opening tapered toward the said first apron for reducing a plurality of strands into a single strand and aligned with the pervious portion of the first apron for guiding the single strand into engagement with that portion of the apron, the said suction means comprising a closed member having a succession of generally elliptical openings obliquely disposed along the path of the apron and adjacent the pressure roll, an elongated opening disposed adjacent the guide bar, and an elongated opening disposed adjacent the tapered opening of the condenser member for drawing a strand in the second-named opening toward the said first apron.

References Cited in the file of this patent UNITED STATES PATENTS 109,430 Leavitt Nov. 22, 1870 2,202,755 Casablancas May 28, 1940 2,219,356 Dreyfus et al. Oct. 29, 1940 2,230,399 Brandt et al. Feb. 4, 1941 2,231,526 Casablancas Feb. 11, 1941 2,306,848 Toenniessen Dec. 29, 1942 2,659,936 Sandelin Nov. 24, 1953 

